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Multicenter Study
. 2025 Apr 21;15(1):13777.
doi: 10.1038/s41598-025-93170-7.

Antimicrobial susceptibility trends of S. Typhi and S. Paratyphi in a post-COVID-19 pandemic India, from a multicenter surveillance network

Nikhil Sahai  1 , Jobin John Jacob  2 , Dilesh Kumar Arunachalam  1 , Bimal Kumar Das  3 , Arti Kapil  3 , Sangeeta Pandey  3 , Shanta Dutta  4 , Debjit Chakraborty  5 , Arunima Sen Gupta  6 , Madhu Gupta  7 , Adarsh Bansal  7 , Bhavini Shah  8 , Veena Iyer  9 , Chinjal Panchal  8 , Shariqa Qureshi  10 , Karnika Saigal  10 , Diganta Saikia  11 , Deepika Gupta  10 , Savitha Nagaraj  12 , Sanju Jose  12 , Maria Thomas  13 , Sangeetha Mohan  13 , Balaji Veeraraghavan  2 , Gagandeep Kang  14 , Jacob John  15
Affiliations
Multicenter Study

Antimicrobial susceptibility trends of S. Typhi and S. Paratyphi in a post-COVID-19 pandemic India, from a multicenter surveillance network

Nikhil Sahai et al. Sci Rep. .

Abstract

We conducted a multicenter surveillance study to identify changes in antimicrobial susceptibility patterns of Salmonella Typhi and S. Paratyphi in India since the COVID-19 pandemic began. We collected S. Typhi and S. Paratyphi isolates from blood or bone marrow culture-confirmed enteric fever cases at eight sites in seven cities across India between 2021 and 2024. We tested the antibiotic susceptibility of 1150 S. Typhi isolates and 265 S. Paratyphi isolates via disc diffusion and determined their minimum inhibitory concentrations (MICs) of ceftriaxone and azithromycin via broth dilution. We identified 18 S. Typhi isolates from Ahmedabad that were resistant to ceftriaxone, indicating a larger emergence of third-generation cephalosporin-resistant S. Typhi in Western India with a novel plasmid profile. Furthermore, we observed yearly increases in the mean, median and 90th percentile of azithromycin MICs for S. Typhi and S. Paratyphi isolates throughout India between 2021 and 2023. Finally, we found that only 0.70% of S. Typhi isolates and 1.13% of S. Paratyphi isolates exhibited susceptibility to ciprofloxacin. Our results indicate the necessity for a shift from ciprofloxacin in the treatment of enteric fever, and the importance of implementing long-term monitoring of resistance to alternative antibiotics such as azithromycin and ceftriaxone.

Keywords: Antimicrobial resistance; Enteric fever; Paratyphi; Paratyphoid fever; Typhi; Typhoid fever.

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Conflict of interest statement

Declarations. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
(a) Distribution of ceftriaxone minimum inhibitory concentration (MIC) values for S. Typhi (N = 1081) and S. Paratyphi A isolates (N = 248); (b) Distribution of azithromycin minimum inhibitory concentration (MIC) values for S. Typhi (N = 1080) and S. Paratyphi A isolates (N = 248).
Fig. 2
Fig. 2
Geographical locations of sites participating in the second phase of the Surveillance for Enteric Fever in India study. The map was created using ArcGIS ver. 10.8 (https://www.arcgis.com/index.html).
See this image and copyright information in PMC

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